This invention relates generally to trigger actuated pump sprayers, and more particularly to such sprayers as having a structure requiring low manufacturing cost and low assembly cost.
It is known for trigger sprayers to have improved ergonomic efficiencies by the provision of a hand positioner affixed to the rear portion of the pump housing as in U.S. Pat. No. 5,172,836, or a hand positioner made integral with the pump housing or with the container, as in U.S. Pat. No. 5,507,437. Such a hand positioner seats against the web of the user's hand between the thumb and index finger during spraying operations to thereby conveniently support especially a large container filled with liquid product to which the trigger sprayer is attached. In the U.S. Pat. No. 5,507,437, the hand positioner is in the form of a rear section of the housing which is hinged to the front section of the housing via a living hinge and is locked in place in a closed position during spraying. The rear section of the housing is hinged for pivotable movement from an open position for molding the housing, to a closed portion for operation of the trigger sprayer. The trigger sprayers of the aforedescribed types have piston return springs which are internal to the pump chamber and are therefore wetted with product which could prove undesirable due to product incapability problems.
Other trigger sprayers are known to include external "dry" piston return springs, as exemplified by U.S. Pat. Nos. 3,768,734, 5,297,701 and 5,299,717. Although the U.S. Pat. No. 5,297,701 discloses a hand gripping formation extending rearwardly from the top portion of the trigger sprayer body, such gripping formation is not in the form of an ergonomic hand positioner or saddle. And, the plastic spring assembly, which urges the trigger together with the piston back into their home positions, is located between the trigger in a position on the body located rearwardly of the trigger exterior of the pump chamber. The trigger lever must be coupled to the piston as the spring acts directly on the trigger for returning the piston out of its cylinder.
To facilitate the molding of especially a low cost trigger sprayer, it is sometimes necessary to provide open access to the pump body through an open rearward section which should subsequently be closed prior to use. As a low cost feature of the trigger sprayer, it would be of an advantage to provide a rear hood for both closing the rearward section of the trigger sprayer body and for supporting an external piston return spring. In such manner, both manufacture and assembly of the trigger sprayer is simplified and the number of parts are reduced to thereby lower the cost of manufacture and assembly. The hand positioner should form no part of the hood to avoid unlocking during use of especially a hinged hand positioner as in the prior art.